Search Publications
Quantitative Evaluation of Coronal Magnetic Field Models Using Tomographic Reconstructions of Electron Density
Arge, C. N.; Henney, C. J.; Wang, T. J. +3 more
We introduce a new quantitative approach for assessing the quality of coronal magnetic field models. The method compares the location of the magnetic neutral line at a specified height in the magnetic field model with the locations of localized density peaks in the coronal electron density, as measured using coronal rotational tomography. This app…
Observations of Current Sheet Heating in X-Ray during a Solar Flare
Reva, A. A.; Kirichenko, A. S.; Ulyanov, A. S. +2 more
In the solar corona, magnetic reconnection occurs due to the finite resistivity of the plasma. At the same time, this resistivity leads to ohmic heating. Therefore, the reconnecting current sheet should heat the surrounding plasma. This paper presents experimental evidence of such plasma heating being caused by magnetic reconnection. We observed t…
Brighter and More Massive Galaxies in the Vicinity of Lyα Nebulae
Wells, Natalie K.; Prescott, Moire K. M.; Finlator, Kristian M.
It has been well established in the local universe that galaxy properties differ based on the large-scale environment in which they reside. As luminous Lyα nebulae have been shown to trace overdense environments at z ~ 2-3, comparing the properties of galaxies within Lyα nebulae systems to those in the field can provide insight into how and when l…
Joint Survey Processing. II. Stellar Proper Motions in the COSMOS Field from Hubble Space Telescope ACS and Subaru Telescope HSC Observations
Fajardo-Acosta, Sergio B.; Faisst, Andreas; Grillmair, Carl J. +4 more
We analyze stellar proper motions in the COSMOS field to assess the presence of bulk motions. At bright magnitudes (G-band 18.5-20.76 AB), we use the proper motions of 1010 stars in the Gaia DR2 catalog. At the faint end, we compute proper motions of 11,519 pointlike objects at i-band magnitudes 19-25 AB using Hubble ACS and Subaru HSC data, which…
Not That Simple: The Metallicity Dependence of the Wide Binary Fraction Changes with Separation and Stellar Mass
Niu, Zexi; Liu, Jifeng; Yuan, Haibo +1 more
The metallicity dependence of the wide binary fraction (WBF) is critical for studying the formation of wide binaries. While controversial results have been found in recent years, here we combine the wide binary catalog recognized from Gaia EDR3 and stellar parameters from LAMOST to investigate this topic. Taking the bias of the stellar temperature…
Dependence of Pulsation Mode of Cepheids on Metallicity
Ren, Yi; Wang, Shu; Jiang, Biwei +2 more
The Cepheid variables in the Small Magellanic Cloud (SMC), the Large Magellanic Cloud (LMC), the Milky Way, M33, and M31 are used to examine the dependence of pulsation mode on metallicity, which was previously found in red supergiants. The initial samples of Cepheids are collected from the Cepheid catalogs identified from the Optical Gravitationa…
Scattered Light in the Hinode/EIS and SDO/AIA Instruments Measured from the 2012 Venus Transit
Young, Peter R.; Viall, Nicholeen M.
Observations from the 2012 transit of Venus are used to derive empirical formulae for long- and short-range scattered light at locations on the solar disk observed by the Hinode Extreme ultraviolet Imaging Spectrometer (EIS) and the Solar Dynamics Observatory Atmospheric Imaging Assembly (AIA) instruments. Long-range scattered light comes from the…
X-Ray Spectroscopic Evidence of Charge Exchange Emission in the Disk of M51
Wang, Q. Daniel; Zhang, Shuinai; Sun, Wei +3 more
In the disks of spiral galaxies, diffuse soft X-ray emission is known to be strongly correlated with star-forming regions. However, this emission is not simply from a thermal-equilibrium plasma and its origin remains greatly unclear. In this work, we present an X-ray spectroscopic analysis of the emission from the northern hot spot; a region with …
Gaia GraL: Gaia DR2 Gravitational Lens Systems. VII. XMM-Newton Observations of Lensed Quasars
Djorgovski, S. G.; Connor, Thomas; Walton, Dominic J. +23 more
We present XMM-Newton X-ray observations of nine confirmed lensed quasars at 1 ≲ z ≲ 3 identified by the Gaia Gravitational Lens program. Eight systems are strongly detected, with 0.3-8.0 keV fluxes F 0.3-8.0 ≳ 5 ×10-14 erg cm-2 s-1. Modeling the X-ray spectra with an absorbed power law, we derive power-…
Lithium Detection in Red Supergiant Stars of the Perseus Complex
Dalessandro, E.; Sanna, N.; Mucciarelli, A. +3 more
We present the first systematic study of lithium abundance in a chemically homogeneous sample of 27 red supergiants (RSGs) in the young Perseus complex. For these stars, accurate stellar parameters and detailed chemical abundances of iron and iron peak, CNO, alpha, light, and neutron capture elements have already been obtained by means of high-res…